LOS ANGELES, March 25 (Xinhua) -- Researchers at the University of Southern California reported Wednesday that they have identified a signaling pathway that helps regulate the movement of blood-forming stem cells.

"The finding provides important new insight into how stem cells move around the body and may lead to improvements in the efficiency of bone marrow transplants," researchers said.

The study will be published in the journal Nature, and is available online on Wednesday.

"By identifying the key mechanism by which these stem cells home and engraft to the bone marrow, it may be possible to pharmacologically treat the cells to activate this pathway and thus increase the effectiveness of bone marrow transplants," said lead researcher Gregor Adams.

Hematopoietic stem cells are blood-forming cells that circulate through the body shifting back and forth between the bloodstream and bone marrow. When patients receive a bone marrow transplant, healthy blood stem cells are injected into their veins. Unless those stem cells can find their way into a specific site known as the stem cell niche, they cannot develop properly to replenish the white cells, red cells and platelets in the patient's blood.

The mechanisms that guide the cells during this migration have not been well understood. However, in this study the researchers found that blood-forming stem cells that lacked a specific signaling molecule, called GalphaS, did not home to or engraft in the bone marrow of adult mice, Adams said.

"Here we show that the GalphaS pathway is a critical intracellular pathway involved in this process," he said.

Currently, large numbers of blood-forming stem cells are required in bone marrow transplantation due to the limited efficiency of the homing process. This study opens up the possibility of treating bone marrow cells with GalphaS pathway activators as a means to increase the effectiveness of bone marrow transplants.